A theoretical analysis of the mechanics of the left ventricle has been undertaken in which the myocardium is modeled as a fluid-fiber continuum. A time dependent length-tension relation is applied to the three-dimensional architecture of the myocardium. The antisotropic elastic behavior is cruicial to understanding the contractility of the myocardium, the development of systolic pressure, pumping of blood out of the ventricular chamber, and the flow of blood in the myocardium itself.